The major objective of the proposed study is to characterize chemically the prostaglandins and related substances released by normal and diseased lungs. At present, most of what is known about the chemistry of the pulmonary prostaglandin synthetase system is based upon studies using microsomal fractions in vitro or studies in which prostaglandin-like substances released by intact lung were examined by bioassay detection systems of indefinite specificity. The former studies have yielded data primarily on the synthesis of PGF2 alpha, while the latter studies have focused on PGE-like compounds. Thus the major technical approach of the proposed study is to apply chemical characterization methodology to clarify the nature and relative abundance of prostaglandins, prostaglandin precursors and possible side- products released by intact lungs in their normal state and under the stress of anaphylaxis or stimulation by kinins. Lungs will be perfused with radioactive (H3 and C14) arachidonic acid. The venous effluent of the lungs will be examined for their contents of radioactive prostaglandins and for postulated precursors (e.g. PGG2 and PGH2). Success in these studies should provide information fundamental to an improved understanding of the role of the lungs in prostaglandin synthesis, the effects of synthesis on lung function and dysfunction, and the role of synthesis in the "endocrine" functions of the lungs.